I saw this movie a long time ago. The action takes places in a small town as far as I can remember. The people there get "infested" with some sort of parasite and they start losing their teeth. I only remember a particular scene where the lead character is in the bathroom in front of the mirror and he takes some pliers and pulls out a tooth so that the other people would not suspect he's not actually "infested". I think those "parasites" were of alien nature.
It probably appeared in late 80s or 90s.